This invention relates to cassettes for holding instruments, such as medical and dental instruments, through cleaning, sterilization, storage and use cycles, as well as to methods for using such cassettes.
Attempts have been made in the past to provide cassettes for holding medical and dental instruments and the like while the instruments are being cleaned and sterilized. The sterilized instruments are kept within the cassette until they are ready to be used again, whereupon the cassette is placed at a convenient location for the practitioner who then is provided with the instrument directly from the cassette.
Such prior art cassettes generally include a lower tray member to which an upper cover member is hinged to form an openable and closable enclosure. Means for clamping the instruments between them, such as resilient rubber pads or cushions, are fixed within the lower tray and upper cover members. In use, instruments to be cleaned and sterilized are arranged on the lower clamping means in the lower tray member whereupon the cover member is pivoted to close the cassette so that the instruments are clamped between the upper and lower clamping means. The tray and cover members, which may be formed of metallic or plastic material, have patterns of holes formed in them to allow for an unimpeded fluid flow into and out from the interior of the cassette to facilitate proper ultrasonic cleaning and sterilization of the instruments.
There are several drawbacks in the construction and use of conventional instrument cassettes. A major objection is that they are relatively bulky in size so that only a very small number of the cassettes can be placed in ultrasonic cleaning machines and autoclaves at any one time. The hinged cover construction, as well as the construction of the upper and lower clamping means, are relatively complex, which in turn makes the conventional cassettes expensive in manufacture.
Moreover, it is generally considered prudent to first remove gross debris, such as cement and impression materials in the case of dental instruments, from the instruments, and then scrub the instruments by hand, before subjecting the instruments to ultrasonic cleaning. In the use of conventional instrument cassettes, it is therefore necessary for an operator to manually handle each individual instrument in order to remove gross debris and then scrub it, before placing the instrument into the cassette. This is a relatively time consuming process and increases the possibility of the operator sustaining puncture wounds.
A further problem in the use of conventional instrument cassettes is that once the cassette containing instruments to be cleaned and sterilized is removed from an operatory in a facility having several operatories, it is not a simple matter to return that cassette to the same operatory, or to the same practitioner. Although it is known to associate source-indicating indicia with individual instruments, such indicia cannot be seen while the instrument cassette remains closed.